Illustrator has the 'Transform Each' dialog, but it only allows you to scale multiple objects by specifying a percentage.

Is there any way to specify the size in pixels?

More specifically, imagine I have 10 rectangles on my canvas, and I want them all to be of a specific height. The bar order and position on the canvas matters, so I can't do the 'vertical align to top and then resize group height' trick - they need to be resized in place.

It can set a whole bunch of other values for selected items, too, if you know the names for them (or, if you look up their names in the Illustrator Scripting Guide or in that linked blog post).

Here's a direct download link, and if for some reason that link breaks or it becomes unavailable, here's the current (Oct 2012) code copied and pasted, including John's helpful notes at the top and the original copyright notice added at the end. It says CS-CS4 but I've had it work fine in CS5 and CS6. All credit, rights etc to John Wundes.

/////////////////////////////////////////////////////////////////
// Set All The Things v.1.2 -- CS,CS2,CS3,CS4
//>=--------------------------------------
// Wanna Batch Transform objects? Illustrator has built in tools to resize each selected item,
// but only by percentage, not by hard values. I made this script because I could find no
// native way to set the width of all selected objects to 100px at once.
//
// This script can accept multiple parameters at once.
// To change, for instance, both width and height at the same time,
// at the 'attributes' prompt, enter <b>width,height</b>
// then at the 'values' prompt, enter a comma separated value list like <b>20,30</b>
// If a single value is passed for 'values', that value will be applied to all chosen properties.
//
// Common legal parameter names include, but are not limited to: <b>width,height,top,left</b>.
// Install and use <a href='http://wundes.com/JS4AI/#explore.js'>explore.js</a> on an object to see what other properties can be set.
//
// Update: Based on feedback from user Jode, You are now given the option to transform objects from center.
// You can now also use whatever standard units you like and the script will convert them into pixels.
// e.g., you can enter "30mm" or "12in" and the script will know what you mean.
// v1.2 adds decimal support and explicit 'px' and 'pt' units to the regex. (thanks to Cristofer Cruz for noticing the bug)
//>=--------------------------------------
// JS code (c) copyright: John Wundes ( john@wundes.com ) www.wundes.com
//copyright full text here: http://www.wundes.com/js4ai/copyright.txt
//////////////////////////////////////////////////////////////////
var centerObjects= false;
function main(){
var item,center_point;
var toPixels=function(v){
var units={
'in':72,
'mm':2.8346455078125,
'px':1,
'pt':1,
},re = /(\d*[.]*\d+)(mm|in|ft|cm|px|pt)/i,m,u,rep;
//derivitave
units['cm'] = units['mm']*10;
units['ft'] = units['in']*12;
while(m=v.match(re)){
u = m[2].toLowerCase();
if (units[u]){
rep = (m[1]*units[u]);
v = v.replace(re,rep);
}
}
return v;
}
var trace = function (m){alert(m)};
if(activeDocument == null){trace("No open document found. Please open a document.");return;}
if(activeDocument.selection.length == 0){trace("Nothing selected. Please select one or more items.");return;}
var i = prompt("What attribute(s) do you want to set?","width,height");
if( i===null ){return false;}
var v = prompt("What value(s) do you want to assign?","100,50");
if (v === null ){return false;}
centerObjects=confirm("Transform Objects around center?");
v=toPixels(v);
// here's where we walk through all objects.
var assign = function (i,v){
for (var x=0 ; x < activeDocument.selection.length ; x++){
item = activeDocument.selection[x];
//get top and left width and height values
center_point = [item.top-(item.height/2),item.left+(item.width/2)];
item[i] = eval(v);
//redraw();
if(centerObjects){
//center_point = [item.top+(item.height/2),item.left+(item.width/2)];
item.top = center_point[0] + (item.height/2);
item.left = center_point[1] - (item.width/2);
}
};
}
if( i.indexOf(',') !== -1){ i = i.split(',');}
//split if a list, but not if function is found.
if( v.indexOf(',') !== -1){ v = v.split(',');}
if(typeof i !== "string")
{
for ( var len=i.length,c=0;c<len;c++)
{
assign(i[c],typeof v !== 'string' ? v[c] : v);
}
} else
{
assign(i,v);
}
redraw();
return true;
}
main();
/*-
* Copyright (c) 2005 wundes.com
* All rights reserved.
*
* This code is derived from software contributed to or originating on wundes.com
*
*
* Redistribution and use in source and binary forms, with or without
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* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by wundes.com
* and its contributors.
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* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
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